Effects of the bradykinin antagonist, icatibant (Hoe 140), on pancreas and liver functions during and after caerulein-induced pancreatitis in rats

Abstract

It has been found earlier that the bradykinin antagonist, icatibant (Hoe 140), prevents the pancreatic oedema and the ensuing hypotension and haemoconcentration, and facilitates the removal of activated enzymes from the tissue during caerulein-induced acute pancreatitis. For a potential therapeutic use of the compound in clinical situations it is essential to investigate whether the associated increase in enzyme activities in the blood serum has any adverse effects on the pancreas itself or on other organs.

Normal amylase secretion into the biliopancreatic duct stimulated by a low dose of caerulein (0.4 nmol kg⁻¹ h⁻¹, i.v.) was not affected by icatibant (100 nmolkg⁻¹, s.c.). Acute pancreatitis, induced by a high dose of caerulein (4 nmol kg⁻¹ h⁻¹ for 2 h, i.v.), resulted in elevations in the activities of amylase and lipase in the pancreatic tissue and in the blood serum lasting for at least 4 h after the end of the caerulein infusion. While the rise in enzyme activities in the blood serum was augmented in icatibant-treated rats only at the end of the caerulein-infusion, the enzyme accumulation in the pancreas was significantly reduced by icatibant for at least 4 h after the end of the caerulein infusion. The secretion of amylase and lipase into the biliopancreatic duct was significantly increased only during the first 20 min of acute pancreatitis; in rats pre-treated with icatibant, no significant increase could be observed. Twenty-four hours after induction of pancreatitis, a low-dose caerulein stimulation of the exocrine function of the pancreas led to a reduced but sustained secretion of amylase regardless of whether the animals had received icatibant or not. During the first 45 min of pancreatitis, blood glucose concentrations were significantly reduced, but returned to values not different from those obtained in saline-infused controls. This effect was not affected by icatibant. No changes in the response to an i.v. glucose tolerance test were found on the day after induction of acute pancreatitis. The serum activities of glutamic pyruvic transaminase and γ-glutamyl transpeptidase determined up to 24 h after induction of pancreatitis were not different from saline controls. Icatibant had no effect on the activities of these enzymes.

It is concluded that during caerulein-induced acute pancreatitis normal exocrine secretion of pancreatic enzymes into the pancreatic duct ceases almost immediately. Pre-treatment with icatibant significantly reduces the accumulation of activated enzymes in the pancreatic tissue for several hours after induction of pancreatitis while a concomitant augmentation in enzyme activities in the blood serum lasts much shorter. There is no indication of adverse effects on the function of the endocrine or exocrine pancreas and that of the liver, either during the acute stages of pancreatitis or during the recovery period.